Hi
when it comes to texting I highly suggest you look up articles on the subject.
But when it comes to my two cent if the girls know you already try to shoot for a meet up or a date. If they don't you I highly suggest you wait for the fall to me them. Then you can start texting and try to me up after classes.
However if your in a group chat and some of the girls seem to like you I suggest you try to PM them. Text a little then try to meet up. Point is to get out of texting and try to see them in person.
Hope that helps