[censored] it, ill try tomorrow, I just need to find the proper words to ask her !!!!
"Hey, you wanna go grab a beer after work?"
"Hey, you wanna go get a coffee at lunch?"
"Hey, you wanna see that new movie?"
seriously, don't overthink this. You don't need to serenade her.
Just
Ask
Her
Out
Also the group thing is to ease any potential awkwardness, in case things don't go your way
Also, the group thing is easier to ask her out on then a single thing if you're nervous.