If you are skinny (or even not so skinny), I would strongly recommend you try the short cannula version (13mm long ) rather than the standard 17 mm set.
AVOID the 'serter! Its a monumental PITA to use and tend to result in bent cannulas. Manual insertion is easy to do - here’s a Youtube video showing you how to do it.
My slight variation on this (as taught by my first DSN) is to first pinch the two side paper tabs between thumb and middle finger and squeeze them together so you are now also gripping the sides of the plastic set. Peel off the front tab and use your free index finger to hold the front of the sticky patch backwards away from the skin. Remove needle cover and insert needle (about 30 degrees but it is not critical). Move your index finger to release the front part of the patch and stick it down. Squeeze the sides to release the needle and withdraw it. Then you can peel off the remaining protective paper and stick the rest of the set down.
I don’t need to use adhesive, but if you do need it I would just paint the area with skin tac either before or after inserting the needle. With the manual insertion as described above, there is no chance of accidentally sticking the paper to your skin as you use the thumb, index and middle fingers to hold the patch away from the skin until you stick it down.
Good luck
After 9 years, I can do the whole operation in less than 10 seconds.
I don’t find the angle particularly critical especially with the 13 mm sets. Stick the needle in at anywhere from around 30 to 45 degrees. Peel off the protective paper from the sticky patch under where you have inserted and stick it down. Hold it in place with one had and pinch and withdraw the needle with the other. Peel off the other protective tab and stick the set down.