I emailed Joe in a different department for help/lots of questions on a new project. Basically "do you have info on this or do you know someone who does"? Joe responded saying "I'm sure Liz can help you, she knows all about this. I've cc'd her on this email"
How do I proceed? I want to thank Joe for putting me in touch with the right person, should I do so separately? Do I reply all and thank Joe while also introducing myself to Liz? Do I email Liz separately and ask for her help or wait for her to reply in the chain since she now has my original email with the questions I asked?
Note: I'm an entry level employee who was told to reach out to this other department. I don't know these people and they are in higher up positions than I am so I want to be extra respectful.