First, glyphing! Of course, read
this if you haven't. <333
1) No, you do not always have to use a scroll. It is the textbook application of glyphs, but not the sole application of glyphs. They can be affixed to items, and drawn on surfaces, so on and so forth.
2) I am not so sure what you mean. If you mean spell-wise, yes. These runes have no power of their own, but can manipulate magic from another discipline, for example storing, releasing, channeling, deflecting or confining a spell.
Next, summoning!
1) First you draw a magic circle, then you activate the magic circle. There are various types of magic circles, and they are work a bit differently, but their purpose is the same. To summon and contain the alien creature, as well as some other uses, I am sure. Activating it requires a drop of the caster's blood, as well as for the caster to know the coordinates of the planet he is summoning from. I would REALLY read
this for that. Summoning is a bit hard to explain here, while keeping to short and simple. I gave a very brief and incomplete overview, best to read the article yourself.
2) Yes, you could. Glyphing is not needed, but it really helps to strengthen the circle, help contain the alien creature, etc etc.
Ancient tongue, you mean? I direct you to
this article. If your character knows it, however, perhaps write the English version of the words in a font unique from your normal speech, and make a small OOC note that whatever that unique font is, is actually your character speaking the words in Ancient tongue?
Just a suggestion! Hope I helped!