hi im new here, im 17 and, about 5'8 and weigh around 120. Last year i began to work out with bench and weights and although i added a little muscle visibly on my chest overall i wasnt very satisfied with my progress. i think however i could easily remedy this with more knowledge, dedication and a better diet.
anyway i have some general questions about what sort of routine i need to use to be successfull in bulking up.I numbered the questions so you dont feel obliged to answer everything and also to make everything clearer hehe.

1. in a week how many days should i be lifting and what should i be doing on other days? ive read in some places you should lift one day rest the next or you should lift one day and do cardio the next. but looking at other peoples routines on this forum most people seem to be lifting most days. does that affect your gains or not?

2. what sort of exercises should i be doing if i want to bulk up generally and is there an ideal way to split them? is it best to focus each body part with a group of exercises on a certain day or just mix them in any order?

3. how many exercises should i be doing? - both overall and in each session? and how long should each session last? before i would do 3 exercises one day, a different three the next, on the third day repeat what i did on the first and the fourth repeat what i did on the second and rest on the fifth. each session would take about an hour?

4. ive read that in order to stop yourself plateauing you should constantly change your routine..how often should i do this and what sort of variety am i looking for?

5. are squats and deadlifts sufficient to workout my leg muscles or do i need to do more specific exercises? my bench only has one of those leg raises things on the end

i think thats all for now