$=\{$a$,$b$\}$Construction technique for reverse and concatenation

Describe the construction technique that is used for the following:

From $2$ dfas that have been constructed for L$1,$ L$1(($a$*($ba $+$ b$))$and L$2,$ L$2(($ab$*$ aa$))$

Using the construction techniques described in class, prove that L$2$L$1$R $($L$2$ concatenated with

the reverse of L$1)$ is also regular.