What do you do when you want to be friends with someone?

[lovemespring]

Aight so theres this girl who im friends with but not super to the point where i can just pull up to her dms like beep beep bitch i wanna talk. I really wanna be better friends w her but don't want to seem persistent or whatever. Doesnt help that we're both bi so she might think im onto her (she cute ngl but thats dangerous turf). Another complication is that im closer friends with her ex and they broke up only a couple months ago. Her ex is still struggling w the breakup.

Anyways, how do i go about this?