There are two different concepts at play here. Firstly, there is Proficiency. Your 5th edition character has a "proficiency bonus" based on their level -- +2 at level 1. If your character is trained in a particular skill, saving throw, or attack type, you may add this bonus to the result of the roll. You generally don't pick your proficiencies outside of Skills (see below), and as a bard, that means you are trained in:
- Light Armor
- Simple Weapons, Hand Crossbows, Longswords, Rapiers, and Shortswords
- Three musical instruments (your choice)
- Dexterity and Charisma saving throws
- Any 3 skills of your choice.
Secondly, there are the skill proficiencies themselves (page 174, Player's Handbook). While some classes are restricted to picking bonus skill proficiencies from a sublist, Bards have their choice of any of the lot! Just a perk of being a bard!
Your "Folk Hero" background already gives you proficiency in animal handling and survival, so pick from the below list, for your character has a total of Five proficiencies (3 from class, 2 from background), so pick three from these to complete your initial set of proficiencies:
- Acrobatics
- Arcana
- Athletics
- Deception
- History
- Insight
- Intimidation
- Investigation
- Medicine
- Nature
- Perception
- Performance
- Persuasion
- Religion
- Sleight of Hand
- Stealth