I need to know how to build a set of steps. They will come down from a loft in our barn which is 8' off the ground. How long does the stringer? Need to be and what would be a good rise for the steps.the top will be anchor on the face of a 2X8 board and anchored to the concrete floor at the bottom. Thank you for the help. Mike

There are a lot of web sites to help with stringer measurements. This one is easy, there may be easier ones out there.
Building Stairs

Mike,
Purchase yourself a swanson square, and a larger 12" swanson square. the smaller 6" swanson square usually has a booklet with it with all the formulas you'll need. The squares mentioned are shaped like a triangle. Any lumber shed should have them in stock.

you'll need (3) 2x12x12 I also like to add 2x4 to the insides of all 3, that's up to you. It just helps with any bounce it may have.
ill try and keep this simple though building steps is one of the tougher things to learn how to do (correctly)

to simplfi things you have to have a carpenters square (12") to do this.
your rise and run are what you do first, your rise needs to be between 7" to 8", lets make yours 8 so we can avoid fractions. you said you height to the top of the room your goin to is 8ft. which is 96" divide 8 into 96 and that gives you 12. 12 is the number of steps you will have to make. And buying a 2x12x12 will give you just enough.

now the run is what will need to set next, and this will depend on what your using as a tread. I will assume you'll get pine steep treads, you'll need to rip them down to 10 1/4". so your run will be 1" less than that. Making it 9 1/4" take the square and lay it on the board you notice on the edge of the square there are numbers....pick a side hold one side to 8" and the other to 9 1/4" once there both right make a mark on the outside edge of the square. now keep in mind the numbers your marking should also be on the outside edge. dont use the ones on the inside.

once you mard this , repeat the step 12times. after youve mark this, youll need to cut it out with a skill saw and a hand saw to make the final cuts. once this is done you need to measure over at the top 9 1/4" and square this straight down and cut this off. On the bottom measure down 8" square this over. this will be a longer cut than the top was. cut this off.
now make 3 of these.

now pic one. youll need to take off an additionial 1 1/2" off the top end. So measure like you did for the 9 1/4 and take another 1 1/2. this will allow you to pass a 2x8 or 10 behind it. You'll be nailing the outside stringers to the 2x10 and then the middle will just butt up against the 2x10 instead of along side it.
you'll need to do this on the bottom as well.

set it into place and use 12s or 16 penny framing nails to do it.

there is a middle more to this but that is the basics deal good luck and buy the book at Lowe's that comes with the square to help as a guide. Good luck