1. on the new search server, install Sharepoint Server 2013 and connect to an existing Sharepoint Server Farm. After that, you can configure a new search server.
Open SharePoint powershell 2013 administrator and run the following code:
$ Hosta = Get-spenterprisesearchserviceinstance-Identity "devsearch2013"
Start-spenterprisesearchserviceinstance-identity $ Hosta
Get-spenterprisesearchserviceinstance-identity $ Hosta
$ SSA = Get-spenterprisesearchserviceapplication
$ Newtopology = new-spenterprisesearchtopology-searchapplication $ SSA
New-spenterprisesearchadmincomponent-searchtopology $ newtopology-searchserviceinstance $ Hosta
New-spenterprisesearchcrawlcomponent-searchtopology $ newtopology-searchserviceinstance $ Hosta
New-spenterprisesearchcontentprocessingcomponent-searchtopology $ newtopology-searchserviceinstance $ Hosta
New-spenterprisesearchanalyticsprocessingcomponent-searchtopology $ newtopology-searchserviceinstance $ Hosta
New-spenterprisesearchqueryprocessingcomponent-searchtopology $ newtopology-searchserviceinstance $ Hosta
New-spenterprisesearchindexcomponent-searchtopology $ newtopology-searchserviceinstance $ Hosta-indexpartition 0
Set-spenterprisesearchtopology-identity $ newtopology
Devsearch2013 refers to the name of the machine on which the current search server is located. According to the code above, the new search server can be changed by running a sentence.