How do I keep a conversation going with him?

Ok so my friend told me tht he likes me awhile ago. And so the other day he asked me if I had a boyfriend and I said yeah and so he was like oh I was going to ask u out but u have a bf. So weve been talking for ahwile over the past few days and I asked him out cuz I ddnt have a bf I just freaked out. And he said he would think about it? And so now idk wht else to say, we had a conversation. And I mentioned us hanging out this summer and then i said but thts up to u. and he just said k. and hes the type of guy who just gives u answers like O and k. Thts pretty much all he txts back most of the time. And its been ahwile since ive txted him cuz idk wht to say? How do u keep a conversation going with a guy like that?