You need to write custom javascript to validate email field. Use regex to validate email format. Refer https://github.com/techforum-repo/youttubedata/blob/master/aem/custom-validation-multifields-1.0.zip to get validation.js for email validtaion.

Add button resource in component dialog xml <button jcr:primaryType="nt:unstructured" sling:resourceType="granite/ui/components/coral/foundation/button" text="Button" type="button" />   Button resource-https://developer.adobe.com/experience-manager/reference-materials/6-5/granit...

Can you check error logs and share?

Create file in ui.config folder: org.apache.sling.jcr.repoinit.RepositoryInitializer-projectinit.config scripts=[" # These paths must exist otherwise the following ACL applicaiton will fail, resulting in err'ing build create path /libs/cq/core/content/nav/tools/security # Create a group create group...

Seems like access issue. Open admin console https://adminconsole.adobe.com/  and provide access of 'launch" to your user or ask admin to provide you access for your project.

Increase heap size first. Use correct memory parameters[1] either with jar or <crx-quickstart folder>/bin/start script when starting AEM instance. Add/Edit below line of code in start.bat/sh file CQ_JVM_OPTS ='-server –Xms8192m –Xmx8192m -XX:MaxPermSize=1024M and restart the instance. Xms is Min hea...

refer same question here https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/how-to-render-image-via-sightly/td-p/542959  

Use indexing to sort page with its number. Add page number of the child pages as sortable indexed property in oak:index. Use a query with a sort parameter as the page number to list the child pages.

@vishwask7315844 Refer https://github.com/adobe/aem-guides-wknd/releases/tag/aem-guides-wknd-1.1.0    

@ac6600 Add below code in _cq_dialog_/content.xml <imagePath allowUpload="{Boolean}false" autoStart="{Boolean}false" class="cq-droptarget" cq-msm-lockable="./file" ...