how to transfer from ipod classic to ipod touch??

You don't. The iPod touch like the Classic originally did, would get the library from the computer it syncs with.

There is no method for direct transfer between iPods.

If you no longer have the computer the iPod classic was synced with, then you'll need to recover the music from the classic and place it on a computer running itunes so you can then sync it to the new iPod touch. You'll need a 3rd party app that can do this.

A respected member of the Apple support communities, Turingtest2, offers this User Tip with steps on how to accomplish the recovery, and some apps that may help you out:

Recover your iTunes library from your iPod or iOS device

You sync the new iPod touch from the iTunes library that was used to sync the old iPod classic. You cannot transfer directly from iPod to iPod.

Your i-device was not designed for unique storage of your media. It is not a backup device and media transfer was planned with you maintaining a master copy of your media on a computer which is itself independently backed up against loss. To use a device with a different setup you transfer the old library from a computer or a backup directly to the new setup, not the device to the library. Media syncing is one way, computer to device, updating the device content to the content on the computer, not updating or restoring content on a computer. The exception is iTunes Store purchases which can be transferred to a computer.

Redownload or transfer your iTunes Store purchases from an iPhone, iPad or iPod to a computer - https://support.apple.com/en-us/HT201267 - "This feature works only for content bought from the iTunes Store." As of iOS9 it no longer does apps which now must be re-downloaded directly from the Store.

For transferring other items from an i-device to a computer you will have to use third party commercial software. See this document by turingtest2: Recovering your iTunes library from your iPod or iOS device - https://discussions.apple.com/docs/DOC-3991 Even this method may not fully recover what you had in the library originally. For example if in order to save space when syncing you had converted music files to a lower bitrate, or photos to a lower resolution, it is those lower quality files you will recover.

If you subscribe to Apple Music, tracks which are not part of content you have purchased or uploaded cannot be transferred and have to be downloaded directly from iCloud.