Once you line the first board up and fasten it, the rest should follow in suit with the spacers.
I would find a flat spacer that is 1/4 inch.. instead of a round one. If you have bent boards and need to pry them in place that circular spacer(nail, screw,) could dent or mar the wood when you pry it in. I'm thinking of heavy prying.
Lowe's or home depot have big flat washers you can use for a 1/4 inch and it will be a flat surface between the deck boards.
If you're doing this by yourself.. you could put a little wooden dowel or long toothpick in the hole of the washer so it lays on the layed board.. and the new board you're trying to put in.. That way the spacer won't keep falling as you're wrestling with a board.

I agree that once you get the first one down, the rest are easy.

Pick up some free paint mixing sticks at Home Depot or Lowes. Cut them in thirds, drill a hole near one end. Stick a nail thru the hole to keep it from falling thru the gap. Double them up for a larger gap. Works great.

I like to use these handy little spacers. We usually have three of them going as we're decking. They're called Deck Mates. I get then free from my local lumber yard. One side has a light 1/8" fin and the other side has a heavy 1/8".

As far as keeping things straight, lay your first board down straight, then lay a few more. Check the last one layed by eye for being straight and adjust the next one if it needs it. Keep checking by eye every few boards.

I have some paint sticks...theyre 3/16, I need 1/4.
I located some 1/4 inch steel flat iron I'll cut up.
Trex makes a big deal of not putting the screw on the butt end closer than 1". Well I stopped by the display at the limber yard. The installer put most just under 1", none are lined up nice, and two were actually put in about 3/8" in.....can you imagine??? Would you believe NONE of the boards split!

Thats because no one is walking on the display real regular, the only way to make a joint with t-j or most all 5/4 composite is to add a sister joist on both sides of the main joist, this is required and in the printed instrustions for installing most 5/4 composite. John