Deadlift (straps) 10x3
45º Leg Press 3x6-8
DB Lunges (with straps) 4x10-12
GHR 3x8
Seated Calf Raises 3x15-20
3x/Week!
Get To It!
^ basically what he said. By the look in your pics you REALLY need to add muscle so start a strengh program and eat at your TDEE.
Yes I know I'm pretty weak. But this is why I'm here

I need a gym membership or at least more equipment to do these exercises. But that's gonna be expensive

What equipment do you have? How much weight? Barbells?
3 dumbbells, 2 x 5kg and 1 x 10 kg. My parents hate weights and they're not gonna pay me the gym-membership. I buy new weight plates & equipment if it's really necessary. But I don't know if I need Barbells yet.
You don't really need barbells, dumbbells can be used. You will some more weight though, getting bigger is all about adding resistance, if your to use those 5kg and not increase them, there will be no increase in size neither.