First of all think of Hadoop as a bundle of services running together, in different nodes in a cluster.
You need to install Hadoop using the zipped version (tar preferably), you can refer to this link https://www.edureka.co/blog/install-hadoop-single-node-hadoop-cluster
I think HDFS and mapreduce come from different rpm packages, but it does harm to install both rpm packages. Again just run NameNode and DataNodes if you only need HDFS.