Creating a friend group in sixth form

Me and my friend are currently in sixth form in year 12, we usually stick together at break and lunch and in free periods, since then it's just been us. Before, in secondary, there were people we knew, but now there's people that aren't there. However, we both were thinking that if we had just 1 or 2 more guys it would be fun especially having a friend group. Any advice? Also how would we start the friend group?