Relationship between sequencing lane and ngs dataset
If you have used adapters containing barcode sequences (that identify each patient), you would presumably end up with one single tube with your libraries in it right?


Correct, you have to prep each sample into a library.


  If so, you then "put" the contents of that tube along with DNA polymerase and nucleotides into one single lane of a flow cell?


You could, or you could pool it with other samples (assuming they have compatible indices). As @swbarnes2 mentioned, you don't see a lot of samples run on a single lane these days. Sequencing centers like to split things across lanes in case on lane fails for some reason or there are bubbles in the flow cell or other technical issues.


  Your provider would then give you raw FASTQ files that have been identified using this barcode?


Typically, yes, and if your sample was run on multiple lanes they'll often be merged for you automatically. This isn't always the case. I've seen a number of people receive samples either still split by lane (annoying, but you can just cat things together) or, much worse, not demultiplexed at all. In the latter case, people often receive 3 (or 4) fastq files per lane, one for each read and another for each index read. It's rare that sequencing facilities do this, but it happens.


  If you do not use adapters with barcodes, does that mean you would have to use a sequencing lane per patient? If so, that would vastly increase the price you pay your provider, would it not?


You could sample a sequence per lane. Whether that makes economic sense is up to you to decide.