Hey Eriias
you heard right, that today damage dealers either are specified into magicka or stamina. when i say that, i mean that they really put everything into one ressource. so magicka templar damage dealers have all their attributes spent into magicka, while the stamina toons have everything into stamina.
regarding skill its pretty much the same: to deal damage only skills either costing magicka or stamina are used. on a magicka character not only the damage skills cost magicka, also most buffs do so. on stamina toons, there may be some buffs costing magicka.
now why do they do that, its simple. the damage done by an ability costing magicka scales with the spelldamage and the maximal magicka pool. so the higher both of them, the better the damage. same goes for stamina skills, they scale with max stamina and weapon damage.
an example would be puncturing strikes, the magicka morph scales with your magicka attributes (spelldamage and max magicka), while the stamina morph benefits from stamina and weapon damage.
also the race has some impact on the damage, since they sometimes give you additional stats, resource management or higher damage.
now also the crit value is very important, since a critical hit is much stronger than a normal hit. therefore weapon crit is important for stamina chars and spellcrit is important for magicka chars.

first off you should decide, which resource pool you want to prioritize a for your damage skills. maybe you already have chosen a good race for one specific spec.
second you should spend all your attribute points into said resource pool, to increase your max stat and therefore the damage of your abilities.
afterwards, there are many sets out and you should focus in sets, that give you a lot of magicka, spell damage and spell crit if you have chosen magicka. if you go stamina, you should aim for sets with weapon crit, weapon damage and max stamina boni. easy sets to get are hundings rage or julionas. they are both craftable and both give you two times crit, once max stat and the last bonus is 300 damage. julionas is the magicka set and hundings rage the stamina version.
also your weapon choice is very importan, since it gives you acces to a lot of additional abilites to us together with your class abilities. best stamina weapon type is dual wield to dish out a lot damage. this is mostly paired with a bow on the second bar. for magical damage destruction staves are the way to go, especially the inferno staves. healing staves belong to the healers tough.
i hope this write up helps a lot to understand the base game mechanics, maybe now some guides on youtube make much more sense. there surely are also guides on youtube, which explain again the base mechanics and also class specific beginner guides. have a look at the skills and setups they use there, because the used setups and skills there are very efficient.
have fun and enjoy the game, i hope i was a little bit of help

If you want to dps on a stamina templar dd, puntiring sweeps, bit actually the stamina morph, will be your spammable. Its a really hard hitting ability when you go for stamina and weapon damage. I would suggest, that xou just once try out a full stamina templar dps build, everything put into stamina with sets, attribute points and cps to just try it out. Maybe you will like, what you experience (especially killing enemy npcs fast is such a time saving and nice experience).