How do I approach gay dating apps when I'm afraid to talk to guys?

I'm pretty insecure about myself and usually on these apps, mainly scruff, I don't know what to do lol. I'm kinda selective I guess and I'm not really looking to hook up or anything, but I don't know what to do on the app especially when I get messages from guys I may not be into let alone guys that I find cute I overthink it and don't respond or anything. Any advice?