Fi, before I answer your question, I want to let you know what you're getting into with PB.
PB is an INCREDIBLE program. Unlike Mario Builder, PB is unbelievable in what it can do. It's not quite up to par with programs like Game Maker, but for what it can do without needing to learn complicated programming languages, you can do pretty much anything you'd like with it, as long as it doesn't involve things like complex physics, tilting ground tiles, and things like that. Pretty much anything can be done.
I strongly suggest you watch the new PB tutorial series which isn't even a week old to get you started with PB. The old video tutorials are so out of date, they're not worth wasting your time with. You can view them on the Official Platform Builder Website, here:
https://theplatformbuilder.com/tutorials/So to answer your question, of course there's a way to do what you'd like to do. As to how to do it...
You have 2 different ways you can do this. There's the old fashioned way which isn't used much anymore and is less versatile, and then there's the modern way which gives you a bit more options. I'll tell you both methods.
Method #1 (Old Fashioned)
In your item box, you can find what's called a Goal Stamp. Place the objects you would like the player to collect to complete the level, then place the goal stamp on them. In the area settings, in the box at top right corner, select Complete Goal Stamps. (You have to click on text to change stuff.) Then tell it that it completes the level.
Method #2 (Modern)
This method might seem difficult, but in all honesty, it's really easy. This method utilizes Command Prompt. Platform Builder's "programming language." TingThing says it's somewhere between a spoken language, and telling your phone what to do. In other words, really easy to learn. All you need to do is learn the commands. There's probably 400+ commands now plus variations etc, and it might seem overwhelming, so just do experiments and get used to using them.
In this instance, we want to use variables. Basically, a variable is a number stored on the computer which can be referenced later on. You can check if the number equals something to make PB do something.
First, create your item. Then, check the Command box, select it, then in the bottom right corner you'll see a command prompt box, click that, then type,
Var + (any name you want, EG: item_level_complete)
If var (any name you want, EG: item_level_complete) = (the number of items there are in your level)
{
complete course
}
You're telling PB that every time the item is collected, your variable adds 1 number to itself. Then you're asking if the variable equals the amount of items in your area (you'll have to manually count them.) Then you're saying that if that is the case, complete the course. And that's it!
