First time installing a PSU and cords

Each cord coming from the PSU likely has more than one connector on it with the exception of the main mobo cord, the 4-pin 12V mobo cord and the PCIe power cord.

For example my PSU includes, among others, 2 cords that each have 2 x 4-pin molex connectors on them. You can connect more than one device to a single cord i.e. two hard drives to each connector, 1 hard drive and one cd drive, etc...

The order in which you connect the power cords to your devices does not matter. The only issue is making the cables reach all of your stuff.

The 4 pin 12V needs to be connected to your mobo along with the main plug. If you have a PCIe card, the 6 pin needs to connect to that also. Connect all your drives with the flat 4 pin cables. SATA drives have a smaller power interface and will be distinct from the other connectors. If you have any case fans that have the 4 pin connectors plug them in also. Such fans usually have two connectors on them. One in and one out. You plug the PSU connector into the part that it fits into and then continue on with the fans out connector to another device i.e. another fan or drive.

Some case fans have small 3 pin connectors that connect somewhere on your mobo. Consult your motherboard manual for information on the locations of these.

Also, any unused cables should be tucked away safely somewhere.

Pretty much if it fits it works.

As to the twist tie, if it's a plastic coated one it's fine but don't use the paper coated ones. I'd suggest you get zip ties instead, they are sturdier and easier to get on but not reusable.

Best thing is to read the user manuals for your MB, video card, etc. They will tell you which power connector to attach to MB, to video card, and so forth.