What do you want to convert?*Races? Open the pathfinder book & record the racial benefits listed. If your race doesn't exist in PF - say Dragonborn - talk it over with whoevers going to DM.
The easiest way is to just use the 5e description/mods. The hard way is to open the Ultimate Race Guide (or whatever it's called - they have a whole book of odd PC races complete with rules for making custom races. Seems like a waste of effort just to copy/paste a dragonborn IMO).
*Stats? Those line up exactly.
*Classes? There's no class that 5e has that's not in PF. Turn to the appropriate pages.
Some of them like the Warlock might work quite differently, but it's somewhere in PF (just not the core book)
Eldritch Knights & Arcane Tricksters are Prestige classes in the core book & will require certain stats/skills/& some MC.
*Lvs/XP?
You've really only got two choices here.
1) Compare the characters existing xp with one of the 3 PF xp charts (Fast/Medium/Slow) & make the PC whatever the matching lv is. The 5e xp chart isn't anywhere near close to even the Slow track in PF, so if this is the route you take the characters will lose lvs.
2) Make the character the same lv as they already are & just set their existing XP to the min. for that lv.
Items? There's nothing in 5e that's not in PF.
How you calculate attack bonuses, saves, skills, etc - just follow the PF book.
Feats are a bit different. And there are ALOT of them, even in just the core book. To start with they're built into the system. Next, some of what 5e does with 1 feat requires several in PF. Including being able to make a full move & do something.
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