I am trying to put a new bathroom downstairs. I have the sink, toilet

Have you looked into a contractor or a plumber?

You will have to tap into your water supply lines and drainage lines. If you aren’t experienced with plumbing and electrical you will probably want to hire a contractor. Those are rather large ticket items within serious consequences if you make a mistake.

I would add a licensed contractor, call around and get bids on the job. Look to Angie's list as a starter.

You will need a plumber and an electrician to install the basics unless you already have those skills yourself. If you tell us a bit more, we can help you out with the lay-out of the room.

Is you plumbing in place. sewer and sink drains, hot and cold running water??

it depends on where your plumbing lines are as to how you lay it all out

I would call a plumber and electrician to do the wiring for lights, etc and that way if there is an issue it is on them and not you

What is your skill set? You will need to pull a permit if doing the work yourself, a plumber, electrician and possibly other trades depending on what you may need. Flooring? Cement backerboard and greenboard for the walls, especially if there is no window to open to release humidity, a ceiling fan so the room doesn't mold, sewer connection, etc. If you need to hire out, only hire licensed professionals otherwise if something goes amiss you won't have any recourse, nor will your homeowners insurance cover any of the damage. This is an investment in your home that will raise property value. Why risk It?

If you are going to sell your home at some point you'll want to have it permitted.

As in "putting it all together" do you mean to install it all? You may need someone who is good at plumbing to help you out.

I would contact a contractor and also your local building department. Oftentimes, you need permits to add bathrooms.

Hi Marie, you want to install the plumbing first, I would do the painting and flooring , then add the fixtures, hope this helps you

https://www.youtube.com/watch?v=70bVcAc9NbA

You need a plumber you need a drain put in for shower sink and toilet

Do you need a permit for any of this? The reasons you need one vary from place to place. Give your local planning department a call or check them out online. There should be info regarding what is required in your area.

You need to call a licensed plumber. Water is not to be messed with as any tiny leak will cause incredible damage.