Confusion on what Paladin spells I can use.

I am new to D&D, only played a couple of sessions, and have just got to lvl3 with my paladin so picked my oath. I have a players hand book and have been using OrcPub/DungeonMastersVault to create and save my character sheet for home sessions and found a pdf online that allowed me to print off spell cards. Now the query, is there a list that breaks down what spells i can access as a paladin with an oath of X, as OrcPub/DMV has said that as a oath of devotion paladin i have access to spells that the pdf spell cards say are oath of the crown spells. or is it just all dependant on which book you are using, as i could see a situation where because i purchased a new book, that added another oath option, i suddenly lose access to some of my spells.

So theres a list of Paladin spells that you always have access to, but you pick a number of spells that you prepare for each day. I forget the exact formula, but i believe its your charisma modifier plus half your level, rounded down, but a minimum of one. So in your case its a minimum of 1 and a maximum of 6. But your Oath adds two spells at level 3 (more at 5, 7, 9, 11, i believe) that are not necessarily Paladin spells, that are always prepared and do not count against your maximum number of prepared spells. I looked it up and as a Devotion paladin your oath spells are Protection from Evil and Good, and Sanctuary. One is a Paladin spell, and Sanctuary is a Cleric spell. 

Thank you, I knew about you having to prepare # of spells per day from the list of spells you know. My query was more along the lines of, my PHB has a choice of 3 different oaths, I know that other oaths are available in other books like the oathbreaker is in the Dungeon Master's Guide. The pdf of spell card s i downloaded had all of the official spells, no homebrews, that a paladin can know, and marks on each card if it is oath specific. My issue is that I seem to have access to 'Compelled Duel' and 'Command' but the cards say that they are oath specific to the oath of the crown. I was wondering if someone had a list of spells that every paladin can know regardless of oath, and then a section that says if you are oath A you have access to X,Y&Z specific spells.

Without the purchase of the Players Handbook on the Roll20 platform, there is no way to break down the spell list to account for sub -class, save for the one subclass allowed by the System Reference Document , the subset of the rules provided for free by Wizards of the Coast. If you are using the paper PHB, or other legal source, you'll have to use that as a guide for which spells to pick, and either alphabetically scroll through the compendium sidebar in game, or use the search field.

I spoke to some people on another site and found the error in my understanding. i have those spells as they are available to all paladins but the oath of the crown has them as the oath spells,so as Anung said they are always prepared.