Shippy

Hi there! My name is Liam, I’m 18, and am mad in love with old school/style bikes. I come asking for some advice/help. I bought a Yamaha SR125 off my pal, but there is something wrong with it. It doesn’t start. At first, I thought it was a compression issue, but it’s not. Then I thought it was because the carburetor hadn’t be cleaned, so I cleaned it out and everything. I then ask my friend what he thinks it could be and he believes the carburetor isn’t sucking the fuel. How could I test if it’s that, or know it’s that? Thank you in advance for any advice!