bwa gatk not found

[Rohit-Satyam]

Hi

I was trying to use bwa instead of bowtie2 But I get the following error

========= F L O W C R A F T =========
Build mode
version: 1.4.1
build: 02032019
=====================================
Checking pipeline for errors...
Resulting pipeline string:

trimmomatic fastqc bwa (spades | skesa pilon (abricate | prokka | chewbbaca))


The process 'bwa' is not available.
Hint: check the available processes by using the '-l' or '-L' flag.

Also gatk can not be found.