PoS structure changes

Updated nav structure
Fixed missing images

Author: arash009

docs/pos/get-started/matic-to-pol.md renamed to docs/pos/concepts/tokens/matic-to-pol.md

@@ -16,25 +16,20 @@ Token mapping is important in order to enable the transfer mechanism for the sai
 
 2. Choose a **Network** option depending upon the chain on which you're looking to map your token. This would be **Sepolia <> Polygon Amoy** for testnet, and **Ethereum <> Polygon PoS** for mainnet.
 
-<center>
-
   ![form-1](../../../../img/pos/token-mapping-1.png){width=50%}
 
-</center>
-3. Next, input the contract address for the token contract that you've deployed on Sepolia/Ethereum mainnet in the **Root Contract Address (L1)** field.
 
-<center>
+3. Next, input the contract address for the token contract that you've deployed on Sepolia/Ethereum mainnet in the **Root Contract Address (L1)** field.
 
   ![form-2](../../../../img/pos/token-mapping-2.png){width=50%}
 
-</center>
+
 4. Choose the correct **Token Type** for your token. i.e., [ERC-20](https://eips.ethereum.org/EIPS/eip-20) for a standard token, [ERC-721](https://eips.ethereum.org/EIPS/eip-721) for an NFT, or [ERC-1155](https://eips.ethereum.org/EIPS/eip-1155) for a multi token.
-   
-<center>
 
-  ![form-3](../../../../img/pos/token-mapping-3.png){width=20%}
 
-</center>
+  ![form-3](../../../../img/pos/token-mapping-3.png){width=25%}
+
+
 5. Finally, select **Submit** to send in your request. The Polygon team will review your mapping request, and get back to you with a response. This generally takes up to 7 days.
 
 !!! info "Token list"

docs/pos/how-to/bridging/ethereum-polygon/submit-mapping-request.md

@@ -267,15 +267,13 @@ nav:
       - PoS: pos/index.md
       - Overview: pos/overview.md
       - Get started: 
-        - Migrate to POL: pos/get-started/matic-to-pol.md
         - Building on PoS: pos/get-started/building-on-polygon.md
-        - Becoming a validator: pos/get-started/becoming-a-validator.md
-      - Builder how-tos:
         - Token bridging:
           - Polygon Portal: pos/how-to/bridging/ethereum-polygon/portal-ui.md
           - Ethereum to PoS: pos/how-to/bridging/ethereum-polygon/ethereum-to-matic.md
           - PoS to Ethereum: pos/how-to/bridging/ethereum-polygon/matic-to-ethereum.md
           - Submit mapping request: pos/how-to/bridging/ethereum-polygon/submit-mapping-request.md
+        - Becoming a validator: pos/get-started/becoming-a-validator.md
       - Node how-tos:
         - Prerequisites: pos/how-to/prerequisites.md
         - Sync node using snapshots: pos/how-to/snapshots.md
@@ -311,9 +309,7 @@ nav:
           - Network upgrade process: pos/reference/network-upgrade-process.md
           - Common commands: pos/reference/commands.md
           - Seed and bootnodes: pos/reference/seed-and-bootnodes.md
-          - RPC endpoints: pos/reference/rpc-endpoints.md
           - PoS mainnet multi-signatures: pos/reference/commit-chain-multisigs.md
-          - Mapped tokens: pos/reference/mapped-tokens.md
       - Governance:
         - Governance fundamentals: pos/governance/governance-fundamentals.md
         - Delegate tokens: pos/how-to/delegate.md
@@ -351,8 +347,12 @@ nav:
             - Reference:
               - Heimdall v2 RPC Endpoints: pos/architecture/heimdall_v2/heimdallv2_rpc
               - Cosmos SDK RPC Endpoints: pos/architecture/heimdall_v2/cosmos_sdk_rpc
+      - References:
+          - RPC endpoints: pos/reference/rpc-endpoints.md
+          - Mapped tokens: pos/reference/mapped-tokens.md
       - Concepts: 
           - Tokens:
+            - Migrate to POL: pos/concepts/tokens/matic-to-pol.md
             - POL: pos/concepts/tokens/pol.md
             - MATIC: pos/concepts/tokens/matic.md
           - Transactions: