All Angels are messengers of the Creator. Indeed, the very word 'Angel' comes from the Greek word 'Angelos', meaning messenger. You could say that Angels are the go-betweens of forces of energy that interact directly between the Creator and mankind.
For most of us, it is easier to relate to angels, whom we are abl to picture rather than the Creator. This is as it should be for the angels are there on behalf of the Divine Creator to guide us by example with their unconditional and non-judgemental love, so that we may achieve our higher purpose in life.
All angels have a supervisory role in the world of mankind; tho they cannot and will not interfere in any way unless we actually invite them in to assist. The key is that we all have free will and can choose whether or not to ask for aid at anytime. Asking for angelic assistance does not mean that a situation you're going through will just disappear, but, you will certainly be given the loving comfort to go through it and emerge the other side with some serenity.
If invited into your life, angels, who are after all charged with overseeing everything that happens in this world by G-d, WILL help and protect your spirit from being broken.
This will help you invoke the angels, and even gives their names and issues they will help with, whenever needed; even as often as you need them so long as you approach them in the right way and with loving intent. Remember .... this is their role as given to them by the Creator and they can be in many locations all at once (omipotent). So don't feel selfish or guilty for callng them down 30 times a day .
Ring that door bell and they will answer! Light a white candle if you so wish.
With this manual, you will be given Angel names/pronounciations, colors and corresponding prolem list. So you can literally 'dial-up' the right angel for the job!