Welcome to the wonderful world of scrapping! It is fun and creative and addictive!!
To avoid that feeling of totally screwing up remember two things... never use original photos or anything that can't be duplicated. And scrapping is ART... and art is subjective.... so if you like it, that is all that counts!!
Maybe start with a small project to get your feet wet. Pick a weekend trip away or a one or two day event and scrap that. Then you will have started and completed something small and you may be feeling much more confident by the end.
If you were my friend and you came to me with these questions I would add the following suggestions....
Check out Simple Scrapbooks magazine. Lots of nice, easy, basic simple ideas. Creating Keepsakes is also a great magazine, but some of the ideas and layouts are much more complicated.
Buy just the basics to begin with (cardstock, adhesive, black journaling pen, good scissors, 12" trimmer, a FEW sheets of patterned paper themed to whatever you are working on). It is too easy getting caught up in buying lots of "stuff" and you may find that your style changes over time and you don't really want to use the stuff you bought at first.
Find a good spot in your house to store your stuff and decide where you are going to work. If you are lucky enough to be able to have a dedicated scrapping spot, then WOOHOO! But most scrappers use the kitchen or dining room table. So then you have to have a handy storage spot nearby (closet, cabinet, etc) and you have to be prepared to clean up every time your family needs to sit and eat.
Have FUN with it. When/if it becomes a chore or is stressful, STOP. If it not fun, there is NO sense in doing it.
Journaling is JUST as important as the pictures. Be sure to add the who/what/where/when/why to every event.... and even more if you can.
If you come to the conclusion that there is ONE part of scrapping that you struggle with, don't be afraid to ask for/look for help. For myself that part is the actual LAYOUT of the photos. So I "scraplift" layouts where ever I can. I LOVE the Becky Higgins Sketches in CK magazine (although she is no longer doing them.

) And I like the layouts at
www.pagemaps.com. So I find lots of help there. I actually keep several binders of sketches/maps that I have found and I have sketched myself and I use them every time I scrap.
Well.........that is it for now. Have fun with your new hobby!...........P