I agree with Shari -- make only a 1 pound batch. Better at this point to make modest size batches more often rather than huge batches that you may or may not like. Practice with many smaller batches to gain the skills you need to do this well.
To create a recipe, first read the tutorial to get familiar with Soapcalc. Got to the Soapcalc website at http://soapcalc.net/calc/SoapCalcWP.asp Here are my suggestions for the settings you might want to use for a 100% lard soap --
NaOH is the alkali you want to use
Choose ounces or grams for the units of weight
Enter the weight of fats you want to use. If you are using ounces, enter 16. If using grams, type 500.
Click the button by Lye Concentration and enter 33%
Leave the superfat at 5%
Ignore the fragrance entry
Scroll down the list of fats and find "Lard, Pig Tallow."
Double click on that name to enter it into your recipe.
Are you grinding soap bars to make your detergent? I would use 100% coconut oil for laundry soap. Its much more cleansing than a lard soap and it doesn't make as much soap scum.
If you want to save some money than a 50/50 lard/coconut might do ok.
I understand why you might want to make a large batch of soap for laundry use, but this is your first batch. Do yourself a favor and make a smaller batch so you can learn the process without a lot of obstacles to success. Work up to the larger batches when you have a better handle on the skills.
Lard is not a good choice as a laundry soap. Yes, my grandmother made lard soap and used it for washing clothes, but it's all she had to work with. Lard soap does a poor job of cleaning clothes. We have better choices available to us, such as soap made from all or mostly coconut oil. Even with a coconut oil soap, it's still soap, so I always add washing soda to every load for softening the water and reducing soap scum.
If you want to make a liquid laundry soap, Shari is right -- a KOH-based true liquid soap is far better than the laundry butter stuff that's touted all over the internet.