how to filter the data based on the selection?

You can filter the list and show the filtered list in the UI like this:

<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId,forceCommunity:availableForAllPageTypes,force:lightningQuickAction" access="global" >
    
    <aura:attribute name="DataList" type="List" />
    <aura:attribute name="FilteredDataList" type="List" />
    
    <lightning:select name="Picklist" label="Status" onchange="{!c.onChange}">
    </lightning:select>
</aura:component>
js Controller:
({
    onChange: function (cmp, event, helper) {
        var selPickListValue = event.getSource().get("v.value");
        var filteredList=[];
        var dataList = component.get("v.DataList");
        
        for(var i=0;i<dataList.length;i++){
            if(dataList[i] == selPickListValue)
                filteredList.push(dataList[i]);
        }
        if(filteredList.length>0)
            component.set("v.FilteredDataList",filteredList);
        }  
})