Side boarding

[Imdowd80]

I know that a legal side board is fifteen cards, but my question is can I have a playset of each card, or is it up to me to be like I want 3 of this card and 1 of this card.

[Gorzo]

It's up to you, so long as the total number of that card in your sideboard and main deck together is still no more than 4.

For example, if you have 2 {doom blade}s in your deck, your sideboard can have 1 or 2 more {dooms blade}s as 1-2 of its 15 cards. If your deck has 0 blades, your sideboard could have 1-4 of them as 1-4 of your 15 cards.

[Imdowd80]

So if I side board 4 {doom blades} I only have 11 spots left?  Not 14 cause doom blade is one card.

[Kuberr]

So if I side board 4 {doom blades} I only have 11 spots left?  Not 14 cause doom blade is one card.

You have 11 spots.

4 doom blades is not one card. It's 4.

[Willthomjr]

So if I side board 4 {doom blades} I only have 11 spots left?  Not 14 cause doom blade is one card.

Correct with 11 slots  left.

You have 15 slots for sideboard. Deck and sideboard cannot consist more than a playset of any spell or nOn basic land.

Easy enough?