Right, I'm guessing when you say you want support and they're saying "use photoshop" that you bought a nice theme - maybe with a picture and something "funky" scrawled across it? Or maybe a header banner which looks great but says something like "Every Little Helps" for example? 
No worries, you can come back to that in a month. You don't need photoshop, you can use GIMP which is a freeware and if you pop over to HubSpot blog you'll find some awesome links there showing you how to do the basic stuff - i.e., how to change the text/colour and make it yours. Doesn't matter, you can do it in a month.
As for the social icons, presumably these were present on the theme you bought? So you need to go through each of the menu items on your Dashboard, starting with Appearance/Design settings, or just Settings. It should be a simple case of plugging in your twitter/facebook user names and away you go.
As for a sign-up box, which mail list program are you using? If it's Aweber or Mailchimp then yes, they'll provide you with some basic code but it's very much form over function and until or unless you're wanting to start playing around with css scripts then you're probably better off making a nice "clicky button" (I bet your theme has this function!) and sending them to the sign-up page that Aweber/Mailchimp has given you which is very customisable (is that even a word? 
) and will remove your headache toot sweet.
Don't try and do it all at once, as girlbehind says, just make a list and cross one thing off at a time.
BIG TIP:- Before you start fiddling with and pushing buttons like a 2 year old , go to Tools/Export and export "all" to your computer. This means that if something gets fucked up, then you can restore.
I hope some of this makes sense, please let me know how you get on.