You can DIY a patio - I did.

As Lily Spider said, it is manual labor. Mine took an entire season, primarily weekends - approximately 750 sq. ft.

My suggestion is to visit and speak with a local landscape supply lot or a local brick yard. They can advise you on the depth of and correct base installation for your local soil conditions. Yes, they will offer to install but will gladly sell and deliver materials. Personally, I do not believe home centers offer credible guidance for this type of project.

Basically you'll need to remove sod and top soil to a necessary depth for your patio. Compact your base in 2-3 inch increments using a plate compactor (rental centers have), install weed block plus a 1" layer of sand atop the compacted base, lay the pavers, sweep sand into the spaces between pavers.

How to get started:

Draw a detailed plan - include desired features. Consider sun/shade for their placement. I installed the pavers with a grade away from and crowned toward the sides the house. Plotted my slope at 1/4" per foot (in both directions), drove stakes at 3 foot increments and marked the respective elevation for base/sand/patio surface using a transit.

Before installing the gravel base, I trenched below my excavation and installed PVC as pathway for electricity and natural gas.

Dug holes for and poured concrete footings for a pergola and egress porch.

Ours also has a French drainage system to carry rainwater away from the patio as the lot grading does not naturally carry water away.

I mention these because NO patio installer will think beyond base/sand/pavers. The long-term stability of the patio is only as good as its base - water and freezing/thawing are the biggest issues to address. Don't skimp on the base - I suggest 4-6 inches for your patio and about 10" for a hot tub but local conditions might cause a variation.

Cost - I did ours in 1998. Estimates at that time were in the range of $13-$15 per square foot installed - so 10-12 thousand dollars. Don't remember my total investment but believe it was probably less than 5 thousand plus my labor and includes all of the improvements mentioned above - I know the pergola lumber ran $1,000.

After the patio was complete, I engaged a nursery to design the adjacent gardens which I built in subsequent years.

If you're still up to the task, get started. I'll share my experience and answer questions but am often away from internet (summer/Corvette/travel) so responses may be delayed. We have one of the most welcoming back lawns in the community and I have long ago forgotten the effort necessary to make it happen. Hope this helps. Good luck.