If it is on your property, this is a job for a pro.
If you know where your clean out fitting is located (mine is located next to my foundation, some are in basements), use a flat snake (or fishtape, or pex pipe). You will need a rather large wrench. Be sure to wear rubber gloves and stand back when you open the cap, nasty stuff is likely to come out. Just run the snake down the line until you hit the clog, then poke at it a bit until the water starts to flow.
If your lines are really old, you may want to call a pro simply because it may be collapsed. If you think you have a tree root issue, again that's a job for a pro. It's not worth the price of an auger to diy.
This is a diy job if you dump grease, coffee grounds, etc down the drain or if you have a disposal and don't run copious amounts of water to wash the particles all the way out to the sewer, or if you use heavy toilet tissue (Scott is the best for alleviating clogs) or flush tampons.
If it’s tree roots, after the augering has been done, stop the roots from re-growing with copper sulfate flushed down the toilet once every 3 months spring-fall.
You would need to rent a sewer drain auger from Home Depot if your capable of doing the job. Otherwise call a plumber.