On the v4.5, you have to raise your Tamagotchi to get a job and become successful in life.
If you have played with other Tamagotchi recently, it shouldn't be too hard to figure out the basics, for the most part.
But I'll explain the basics anyway... because I've got a lot of time on my hands today.
The first icon's the check meter, which just shows your Tamagotchi's hunger, happiness, discipline, skill points etc. If any of the hunger or happiness hearts are empty, fill it up. To fill up a hunger heart feed it a meal (this will make your Tamagotchi gain 1lb), to fill up a happiness heart, either feed it a snack or play a game. If you've got the time, I recommend that you play a game. Snacks will make your Tamagotchi gain weight (2lb), while games will make your Tamagotchi lose weight (up to 3lb). Bear in mind that your Tamagotchi won't play games if it's too close to its minimum weight. You can check the weight in the check meter too, if I remember correctly it's the fourth screen.
Discipline doesn't seem to have too much impact on your Tamagotchi's growth on the v4 and 4.5. When your Tamagotchi is crying and still has at least one hunger and one happiness heart left, praise it to comfort it. When your Tamagotchi's just walking around and beeps at you and still has at least one hunger and one happiness heart left, punish it for calling you when it didn't desperately need anything. Of course, if one of your Tamagotchi's meters are empty, fill it up without hesitation!
Next up is skill points. These affect your Tamagotchi's growth and what jobs it can get when it grows up. From top to bottom, they are: Humour/funny (face), Gorgeousness (sparkle) and Passion/spiritual (fist). To increase them, play games. Climb and Tug-o-war increase random skill points. Apples increases humour, Shapes increases gorgeousness and Manhole increases passion. You can also feed special foods which will boost your Tamagotchi's skill points slightly.
I think I've pretty much explained the most important things on the check meter so I'll just explain a couple of other icons. The next one along is food, which allows you to feed your Tamagotchi meals or snacks. The third one is the toilet icon used to clean up after your Tamagotchi. If you see wavy lines around your Tamagotchi, select the toilet icon to make it use the toilet. The fourth icon is the activities icon and has a good deal of options in it.
The first one's Game, and lets you play up to five different games depending on how old your Tamagotchi is. I don't have a v4.5, but I have played on my friend's v4.5 so this is all just from my terrible memory so it may not be correct. In Climb, press any button to jump up on to the next cloud. (Well I'm pretty sure it's any button, though it might just be the B button that works.) Once you get to 24, keep pressing the button quickly to get to 30 easily. (It worked for me when I was playing with my friend's v4.5.) In Tug-o-war, if I remember correctly, press B to stop the meter when it's at its fullest and hope that your Tamagotchi wins. In Apple, press A to face left and C to face right to catch the apples. Shapes is a bit more complicated. You have shapes falling down from the sky, and three shapes at the bottom. Squares need to fall into the square at the bottom, and so on. So you've got to move around the shapes at the bottom. A is for the left shape, B is for the middle one and C is for the right shape. To switch around shapes, press the two buttons of the two shapes that you want to swap around. Finally, in Manhole, hold A, B or C to open the manholes and catch the stuff. Avoid catching bad stuff though.
I'm not going to explain the other four things in the activities menu, most of it should be pretty self explanatory.
The final icon on the top row is IR Communication. But that's not all it does. You still go here to communicate with other Tamagotchi, but here you can also get a password for Tamatown and let your Tamagotchi go to work. The preschool game is just a dance that your Tamagotchi does and you can't control. The school game may need a bit more explaining. You know that game where you have three hats and someone else puts something under one of the hats and then swaps them around, then you need to guess which hat the object is hiding under? This is that game. The two flashing boxes are the ones that are switching around. There are many different work games and I don't know them all. Some are the same as the regular v4, while some are different. They shouldn't be too hard to work out though.
The next icon I'll explain is mail, the third icon on the bottom row. When you've got mail, this icon will flash. Star mail is your fortune cookie which just tells you how lucky your day will be. This doesn't have too much of an influence, though it does have a little impact (if you have 3 stars under wealth, for example, you will get 500p from beating a game instead of just 400). Normal mail is the second option and can be items or money from the Gotchi King, a love heart (which makes your Tamagotchi happier) or something unpleasant, which makes your Tamagotchi unhappier. Finally, the last option is the most important of all. This alerts you when it's time for your Tamagotchi to go to preschool, school or work.
Well, I think that's all of the basics that aren't so self-explanatory. If you have any questions, ask away
