download reads for chromosomes

[me91]

hi, i want to download some raw data with .sra format from ncbi, i need to download reads for specific chromosome like chromosome 2. but i cant find any explanation about which chromosome the reads belong!

how to find which chromosome the reads belong?

[maubp]

If you are starting with raw reads, you must map them to your genome to discover which chromosome(s) they match.

You may be able to find pre-mapped data (e.g. as BAM files), but this depends on which dataset you are interested in, and what the creators of that data opted to do and share.

[me91]

how to map reads to genome? and how to download pre-mapped data?