i want to write a code in R, that reads 2 or more SRA files, and then unite them into a single file, problem is, i don't understand how to operate the SRA data in R, i read around and it suggested to either convert or directly download them in the fastq format, but even doing that, i still don't understand how am i supposed to load the data into R in the first place even when operating with the fastq format

i got myself SRAdb already and with SRAdb i can execute queries on the SRA database and download SRA files, the problem is i don't understand how i can then load the SRA file as data in R in order to create a single file that unite multiple SRA files

Use ShortRead readFastq() / writeFastq() for reading and writing fastq files, including appending files.